Enhanced Photocatalytic Activity of Nitrogen-Carbon Co-Doped Tio2 for Air Pollution Mitigation on Cement-Based Surfaces

Abstract

Global pollution, notably air pollution, is worsening. Applying high efficiency photocatalysts under visible light onto the surfaces of cement-based materials can significantly reduce pollutant concentrations in heavily polluted areas. In this study, carbon and nitrogen co-doped titanium dioxide (C, N-TiO2) and carbon nitride (TiO2-C3N4) composites were synthesized via a calcination method by changing mass ratios of titanium dioxide (P25) with urea. The nitric oxide and formaldehyde degradation efficiencies of C, N-TiO2 increased by 20.3% and 40%, respectively, compared to untreated P25. Additionally, free radical scavenging experiments investigated the mechanisms underlying the photocatalytic degradation of pollutants. The adding of nano-silica as an interlayer not only improves the photocatalytic efficiencies, but also improves photocatalytic durability. The photocatalytic NO degradation performance was tested again after simulating rain leaching to conduct long-term photocatalytic performance. The photocatalytic efficiencies of cement-based sample using nano-silica interlayer increased by 115% than that of no nano-silica sample. After rain leaching, the photocatalytic efficiencies of cement-based sanples with and without nano-silica decreased 7.5% and 36.6%. A mechanism of improved photocatalytic efficiencies and durability was proposed. These findings offer valuable insights for the broader application of photocatalysts on cement-based materials.

Keywords: Photocatalysis, surface treatment, Cement-based materials, Nitrogen-carbon co-doped TiO2, Air pollution